Security Bulletin SC2019-002-312864

This Security Bulletin includes an update regarding a previously disclosed Critical vulnerability (SC2019-002-312864) in Sitecore software, for which a fix was made available in March 2019. This vulnerability could allow an unauthenticated threat actor to inject malicious commands and code, thus compromising the security controls.

Recently, Sitecore has become aware of active exploitation of this Critical vulnerability.

Sitecore strongly recommends that customers maintain their Sitecore environments on security-supported versions and apply fixes to Critical vulnerabilities without delay.

Sitecore therefore strongly advises that all customers on Sitecore versions 8.2 and below apply the Solution, detailed below, immediately. In the event that customers are unable to apply the Solution immediately, Sitecore suggests that customers immediately apply the Alternative Workaround in the interim and identify a way to apply the Solution as a priority.

We encourage Sitecore customers and partners to familiarize themselves with the information below and apply the fix to all Sitecore systems. We also recommend that customers maintain their environments on security-supported versions and apply all available security fixes without delay.

See the readme.txt file inside the archive for installation instructions.

Validation

To verify that the fix has been applied successfully, check the SHA256 hash of the "Sitecore.Security.AntiCsrf.dll" file in the \bin folder of your website. The hash should be the same as indicated below.

Note: Upon implementing this workaround, content editing functionality will not be available in your Sitecore environments.

If content editing functionality cannot be temporary disabled, as an alternative, it is possible to configure IP-based security restrictions for \Website\sitecore\shell folder to block all access for external users and only allow access from trusted IP addresses which malicious actor is not able to use. For instructions on how to configure IP-based security restrictions, see http://www.iis.net/ConfigReference/system.webServer/security/ipSecurity.

06-May-2020: Hotfix validation instructions have been updated to list SHA256 has codes for Sitecore.Security.AntiCsrf.dll file. The hotfix package remains the same and your installation remains secure in case the hotfix has already been applied.